This invention relates to a hand held tool to be used in servicing a conventional vehicular drum brake shoe assembly for capturing a spring-retaining annular disc-like cup and turning the cup relative to a coaxial retaining pin to enable release of a compressed coil spring which positions a brake shoe. When a cup is separated from the assembly to allow removal of a brake shoe, this invention enables a cup to be positively confined but releasably retained in the tool to prevent it from being misplaced or lost. A retained cup can be reinstalled during servicing of a brake shoe by mere manipulation of the tool.
In one form of conventional vehicular drum brake shoe assembly a pair of brake shoes, located generally coaxially within a brake drum on opposite sides of the wheel axis, are held by compression springs against a relatively stationary flat brake shoe supporting plate extending transversely of the wheel axis. The compression springs bear against outer surfaces of flat web portions of the brake shoes. The springs are held in compression by nail-like pins having head portions removably held behind holes in the supporting plate. The pins extend outwardly from the supporting plate through holes in the respective brake shoe webs and through the compression springs and are releasably retained at the other ends of the pins in spring retaining cups.
Each cup has a flat annular flanged rim portion which is concentric with and overlies one end of the coil spring. A bowl portion of the cup fits within this end of the spring to keep the cup and the spring coaxial. At the center of the bowl portion of the cup is a transverse slot through which pass an enlarged flattened tip end of the nail-like pin. In the assembled arrangement of the brake shoe mechanism, the flattened tip of the pin lies in an elongated detent recess or groove extending transversely in the cup bowl. The cup may be removed by pressing it against the spring and rotating it ninety degrees or orthogonally to a position in which the tip may escape through the slot. Most cups are of two common diametrical sizes.
It has been a practice to remove cups for disassembly of the brake mechanism with a tool such as locking pliers, but upon removal of the cup it may be dropped or temporarily misplaced. This makes for inconvenience in handling the cups and also induces wasted time in reassembly unless the cup is kept in the relatively expensive locking pliers. Of course to keep each of the cups ready and easily locatable it would then also take two sets of such pliers to enable cup removal and assembly service on a pair of brake shoes. A problem of time consuming awkwardness exists in trying to simultaneously install a brake shoe, a retaining pin, a compression spring and a spring retaining cup.
The present single or double ended low cost resilient plastic tool has at each cup-engaging end several circumferentially spaced integrally molded or formed resilient detent fingers for positively engaging and grasping an annular peripheral edge of a coil-spring retaining cup in a drum brake shoe holding cup and retaining pin assembly. The tool has a body portion with at least three symmetrically arranged parallel fingers extending from the body portion parallel to an axis of the tool. During use this axis of tool rotation will be oriented perpendicular to the plane of the annular cup edge and aligned with the center of the cup. The tool is manually pushed axially relative to the cup with the detent fingers being forcibly transversely cammed and displaced outwardly during this axial movement of the tool as detent portions of the fingers are forced past the cup edge. The detent fingers provide means configured and arranged to be forcibly manually pushed past the cup edge at points spaced circumferentially around the cup edge whereby the tool provides a retaining cage for positively but releasably retaining the cup. The tool includes contact surface means for frictionally engaging the cup when the cup is in the cage to enable the cup to be rotated relative to the retaining pin when the tool is forcibly manually pushed axially and manually rotated about the tool axis to enable the cup to be positioned for detachment or attachment relative to the pin of the cup and pin assembly.
At least a symmetrically arranged plurality of the fingers at each cup capturing end of the tool are resilient and have portions projecting toward the tool axis to provide displaceable detent means engageable with the cup edge and displaceable relative to said axis by manually moving the tool axially to cam the detent means outwardly as they move over the cup edge for allowing the tool to positively grasp and hold the cup. This cage holds the cup during manipulation of the tool for detachment and attachment of the cup relative to the coaxial pin and retains the cup in said cage when the cup is separated from the pin.
The tool is preferably molded from a high strength durable light-weight resilient plastic. Its low cost enables it to be marketed as an included item in prepackaged sets of replacement brake shoes. Since one set of brake shoes requires only two retaining cups, a single double-ended tool enables a brake mechanic to keep both cups in the tool at all times when removed from the brake assembly while working on one wheel assembly.
A single double-ended tool of proper size will hold the two cups of a conventional brake shoe assembly for one wheel. A set of two tools will take care of the two most popular cup diameter sizes. Preferably each tool will have cup retaining cages of like diameters at its opposite ends, but if the ends of the tool are of different sizes two identical tools will suffice for one wheel.
An object of the invention is to provide a simple low cost small size cup removal tool which takes up minimal space in a tool box or chest.
Another object of the invention is to provide a cup removal tool which may be entirely or partially conspicuously coded by shape or color to enable it to be quickly identified in a tool box for the size of cups to be removed during a brake servicing job. Like sized ends on one tool may be coded alike and different sized ends on one tool may be differently coded.
Another object of the invention is to provide a low cost plastic tool which adds little weight to a tool box or may even be expendable so that it need not be carried at all times in a tool box.